My engine is a V8. Why am I getting P0212?

You should not be. P0212 refers to cylinder 12, which only exists on engines with twelve or more cylinders. On anything smaller there is no cylinder 12 for the module to monitor. The usual explanations are a scan tool misreading the code, a manufacturer-specific code being looked up in a generic table, or a stored code left in a shared reader from another vehicle. Re-scan with a tool that supports your make before buying parts.

Is there a P0213 for cylinder 13?

No, and this trips people up. The generic injector circuit/open family stops at P0212 for cylinder 12. P0213 and P0214 are already assigned to the cold start injectors, which are a completely different component with a completely different job. If you are working on an engine with more than twelve cylinders, the manufacturer will have used its own code numbering for the additional cylinders — look it up in the service data for that specific engine rather than assuming the generic sequence continues.

Why does my V12 have two engine control modules?

Twelve cylinders are more inputs and outputs than a single module of that era was built to handle, so several manufacturers split the work — one module per bank, either as a master and slave pair or as two coordinated units. For this code it means cylinder 12 is driven by whichever module serves its bank. It also means a power, ground, or communication fault at one module can set injector circuit codes across an entire bank at once. If that is the pattern in front of you, replacing injectors will not fix anything.

Can I keep driving with P0212?

Drive it to a shop and no further. A dead cylinder is a sustained misfire, and it pumps unburned fuel into the exhaust where it overheats the catalytic converter on that bank. On a twelve-cylinder engine those exhaust components are expensive enough that letting the fault run is a poor trade against the cost of the injector repair. If the check engine light is flashing, stop driving and have the vehicle towed.

OBD-II trouble code

P0212: Injector Circuit/Open - Cylinder 12

An electrical fault in the cylinder 12 fuel injector control circuit. Cylinder 12 exists only on twelve-cylinder engines, and this code closes out the generic injector circuit family — there is no P0213 for cylinder 13, because P0213 means something entirely different.

Medium severityPowertrainFuel InjectorsDrivable short-term

Quick facts

System: Powertrain
Category: Fuel Injectors
Severity: Medium severity
Drivable: Usually safe to drive short-term
Repair cost range: $80 – $2,500
DIY difficulty: Advanced DIY

What does P0212 mean?

The engine control module (ECM) fires each fuel injector by pulsing its control circuit. Battery voltage feeds one side of the injector and the ECM switches the ground on the other side for a precise number of milliseconds. The module watches that circuit electrically, and when what it sees back does not match what it commanded, it sets an injector circuit code. P0212 isolates the fault to the cylinder 12 injector circuit.

P0212 is the last code in the generic injector circuit/open family. The family runs P0201 through P0212, one code per cylinder, and it stops at twelve because P0213 and P0214 are already assigned to the cold start injectors. That is worth knowing, because it means the numbering does not simply continue upward — if you have a sixteen-cylinder engine, there is no generic code for cylinder 13, and the manufacturer will have used its own numbering scheme instead.

Cylinder 12 exists only on engines with twelve or more cylinders: the V12s from Mercedes-Benz, BMW, Jaguar, Aston Martin, Ferrari and Lamborghini, the W12s from the Volkswagen group, and a range of industrial, marine and heavy-equipment engines. If your vehicle has ten cylinders or fewer, P0212 cannot legitimately apply. The likely explanation is a scan tool misreading a manufacturer-specific code or looking one up in the wrong table, and the right first move is to re-scan with a tool that supports your make before spending anything.

Assuming the engine really does have twelve cylinders, the same structural point that applies to P0211 applies here. Many V12s use two engine control modules rather than one — Mercedes M120 and M275/M279, BMW M70/N73/N74 and others run a module per bank as a master and slave pair or as two coordinated units. Cylinder 12 is driven by whichever module serves its bank. A power, ground, or communication fault at that module can throw injector circuit codes across an entire bank at once, and no amount of injector replacement will fix that. Reading the pattern of stored codes before touching anything is the single most valuable diagnostic step on these engines.

Beyond that, "Circuit/Open" is a description of an electrical condition, not a verdict on the injector. A broken or chafed wire, a corroded or backed-out connector pin, a poor ground, or a blown fuse will all set it, as will an injector coil that has failed open internally. Injectors are fed in groups through shared fuses and relays, so a handful of injector codes appearing together usually means one upstream feed problem rather than several simultaneous injector failures. Back-probe a couple of connectors for battery voltage before assuming you need parts.

The cost picture is the same one that makes twelve-cylinder ownership what it is. These injectors are low-volume parts often sold only through the dealer, access typically means dismantling an elaborate intake assembly, and generic scan tools frequently cannot see the per-bank module data these engines report. Do the electrical testing you can do cheaply, then take clear findings to a shop that knows the specific engine rather than guessing at parts.

Common causes

Corroded, loose, or backed-out connector pins at the cylinder 12 injector
Broken or chafed wiring in the cylinder 12 injector circuit
Open or shorted coil winding inside the cylinder 12 injector
Blown injector fuse or failed relay feeding that bank's injector group
Poor ground or a corroded splice in the shared injector power feed
Power supply, ground, or communication fault at the control module serving that bank on a dual-module V12
Harness damage from earlier work on the intake or valve covers
Failed cylinder 12 injector driver inside the control module serving that bank

Symptoms

Check engine light on, sometimes flashing if cylinder 12 is dead
Rough idle and vibration, unusually obvious on an engine designed to be exceptionally smooth
Loss of power and hesitation under acceleration
A cylinder 12 misfire, often stored alongside as P0312
Raw fuel smell or a jump in fuel consumption
Hard starting in some cases
Several injector codes on one bank if that bank's module or feed has failed

Diagnostic steps

1.Confirm the engine actually has twelve or more cylinders. If it does not, re-scan with a tool that supports your make before spending anything.
2.Record every stored code and map the affected cylinders to their banks. Circuit codes across one whole bank point at that bank's module, power supply, or ground rather than at the injectors.
3.Verify both control modules are powered, grounded, and communicating, using a scan tool that can read per-bank data.
4.Identify which physical cylinder your engine calls number 12 and which bank it sits on, from the numbering diagram for that specific engine.
5.Check the injector fuse and relay for that bank's group first — the cheapest outcome and the fastest to rule out.
6.Back-probe the cylinder 12 injector connector for battery voltage on the feed side with the key on. No voltage means the fault is upstream of the injector.
7.Inspect the connector and harness for corrosion, chafing, heat damage, and backed-out pins, then wiggle-test while watching live data.
8.Measure the injector's coil resistance with the key off and compare it against specification and against the other injectors. An open or badly out-of-spec reading condemns the injector.
9.Use a noid light or the scan tool's injector test at the connector to confirm the module is actually pulsing the circuit.
10.Swap-test with a known-good injector from another cylinder if the resistance is borderline, rather than buying a low-volume part on a guess.
11.Only after the fuse, feed, ground, wiring, and injector all test good should you suspect the injector driver inside that bank's module, since replacing it requires programming.

Repair cost

$80 – $2,500

A wiring or connector repair typically runs $80-$350, reflecting the tight access in a twelve-cylinder engine bay. A blown fuse can be a few dollars. V12 and W12 injectors are low-volume parts often sold only through the dealer, so expect $150-$700 per injector rather than the $60-$400 typical of a V8, plus 1-4 hours of labor depending on how much of the intake assembly has to come off. Diagnosis commonly runs $150-$300 because factory-level tooling is needed to read per-bank module data. A failed injector driver inside a bank control module runs $800-$2,500 including programming, and on dual-module engines the two units usually have to be matched and coded together.

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DIY vs shop

This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.